Apparatus and methods for reducing magnetic field emissions between wireless power transmitters

• US 10,566,850 B2
• Filed: 06/10/2016
• Issued: 02/18/2020
• Est. Priority Date: 06/10/2016
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Percebon, Leandro
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Evans, James P
• Application Number:
  US15/179,854
• Publication Number:
  US 20170358960A1
• Time in Patent Office: 1,348 Days
• Field of Search: None
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

In an aspect of the disclosure, an apparatus for wirelessly transmitting power is provided. The apparatus includes a communication circuit configured to communicate with a first wireless power transmitter and a second wireless power transmitter. The apparatus further includes a controller circuit configured to identify a first phase of a first current provided to the first wireless power transmitter, the first current generating a first magnetic field. The controller circuit further determines a time to provide a second current to the second wireless power transmitter. The controller circuit further provides the second current at the determined time with a second phase having a phase difference between the first phase configured to reduce a magnitude of a combined magnetic field of the first and second magnetic fields in a region between the first and second wireless power transmitters.

Claims

1. An apparatus for providing wireless power to a plurality of devices, the apparatus comprising:

a communication circuit configured to communicate with a first wireless power transmitter and a second wireless power transmitter; and

a controller circuit, in communication with the first and second wireless power transmitters via the communication circuit, configured to;

identify a first frequency of a first current provided to the first wireless power transmitter, the first current generating a first magnetic field at a first level sufficient to power or charge a first device,

determine a second frequency at which to provide a second current to the second wireless power transmitter such that a frequency difference between the first frequency and the second frequency reduces a magnitude of a combined magnetic field of the first and second magnetic fields in a region between the first and second wireless power transmitters, and

provide the second current to the second wireless power transmitter at the second frequency.

2. The apparatus of claim 1, wherein the communication circuit is further configured to receive a measurement of the first current from the first wireless power transmitter.

3. The apparatus of claim 1, wherein the frequency difference is configured to reduce the magnitude of the combined magnetic field from a first level to a second level, the second level lower than the first level and satisfying a safety threshold magnetic field emissions level.

4. The apparatus of claim 1, wherein the controller circuit is further configured to provide the second current through a power transfer link.

5. The apparatus of claim 1, wherein the controller circuit is further configured to:

identify a first phase of the first current provided to the first wireless power transmitter;

determine a second phase with which to provide the second current to the second wireless power transmitter such that a phase difference between the first phase and the second phase reduces the combined magnetic field;

determine a time at which to provide the second current to the second wireless power transmitter; and

provide the second current with the second phase to the second wireless power transmitter at the determined time.

6. The apparatus of claim 5, wherein the controller circuit is further configured to identify the first phase based on the measurement of the first current received from the first wireless power transmitter.

7. The apparatus of claim 5, further comprising a sensor circuit configured to measure the first phase and/or monitor a temperature of the first wireless power transmitter.

8. The apparatus of claim 1, wherein the controller circuit is further configured to determine a time to provide the second current to the second wireless power transmitter at the second frequency such that the magnitude of the combined magnetic field in the region is reduced.

9. A method for providing wireless power, the method comprising:

communicating with wireless power transmitter and a second wireless power transmitter;

identifying a first frequency of a first current provided to the first wireless power transmitter, the first current generating a first magnetic field at a first level sufficient to power or charge a first device;

determining a second frequency at which to provide a second current to the second wireless power transmitter such that a frequency difference between the first frequency and the second frequency reduces a magnitude of a combined magnetic field of the first and second magnetic fields in a region between the first and second wireless power transmitters; and

providing the second current to the second wireless power transmitter at the second frequency.

10. The method of claim 9, further comprising receiving a measurement of the first current from the first wireless power transmitter.

11. The method of claim 9, wherein the frequency difference reduces the magnitude of the combined magnetic field from a first level to a second level, the second level lower than the first level and satisfying a safety threshold magnetic field emissions level.

12. The method of claim 9, wherein providing the second current comprises providing the second current through a power transfer link.

13. The method of claim 9, further comprising:

identifying a first phase of the first current provided to the first wireless power transmitter;

determining a second phase to provide the second current to the second wireless power transmitter such that a phase difference between the first and the second frequency reduces the combined magnetic field;

determining the time to provide the second current to the second wireless power transmitter; and

providing the second current with the second phase to the second wireless power transmitter at the determined time.

14. The method of claim 13 wherein identifying the first phase is based on the measurement of the first current received from the first wireless power transmitter.

15. The method of claim 13, further comprising measuring the first phase and/or a temperature of the first wireless power transmitter via a sensor circuit.

16. The medium of claim 9, the method further comprising determining a time to provide the second current to the second wireless power transmitter such that the magnitude of the combined magnetic field in the region is reduced.

17. An apparatus for providing wireless power, the apparatus comprising:

means for communicating with wireless power transmitter and a second wireless power transmitter; and

means for identifying a first frequency of a first current provided to the first wireless power transmitter, the first current generating a first magnetic field at a first level sufficient to power or charge a first device;

means for determining a second frequency at which to provide the second current to the second wireless power transmitter such that a frequency difference between the first frequency and the second frequency reduces a magnitude of a combined magnetic field of the first and second magnetic fields in a region between the first and second wireless power transmitters;

means for providing the second current to the second wireless power transmitter at the second frequency.

18. The apparatus of claim 17, further comprising means for receiving a measurement of the first current from the first wireless power transmitter.

19. The apparatus of claim 17, wherein the frequency difference reduces the magnitude of the combined magnetic field from a first level to a second level, the second level lower than the first level and satisfying a safety threshold magnetic field emissions level.

20. The apparatus of claim 17, wherein the means for communicating comprises a communication circuit, means for identifying comprises a controller circuit, means for determining comprises a controller circuit, and means for providing comprises a controller circuit.

21. The apparatus of claim 17, further comprising:

means for identifying a first phase of the first current provided to the first wireless power transmitter;

means for determining a second phase to provide the second current to the second wireless power transmitter such that a phase difference between the first phase and the second phase reduces the combined magnetic field;

means for determining the time to provide the second current to the second wireless power transmitter; and

means for providing the second current at the second phase to the second wireless power transmitter at the determined time.

22. The apparatus of claim 21, wherein the means for identifying the first phase is based on the measurement of the first current received from the first wireless power transmitter.

23. The apparatus of claim 21, further comprising means for measuring the first phase.

24. The apparatus of claim 17, further comprising means for determining a time to provide the second current to the second wireless power transmitter such that the magnitude of the combined magnetic field in the region is reduced.

25. A non-transitory computer readable storage medium comprising instructions that when executed cause a processor to perform a method for wirelessly transmitting power, comprising:

communicating with wireless power transmitter and a second wireless power transmitter;

identifying a first phase of a first current provided to the first wireless power transmitter, the first current generating a first magnetic field at a first level sufficient to power or charge a first device;

determining a second frequency at which to provide a second current to the second wireless power transmitter such that a frequency difference between the first frequency and the second frequency reduces a magnitude of a combined magnetic field of the first and second magnetic fields in a region between the first and second wireless power transmitters;

providing the second current to the second wireless power transmitter at the second frequency; and

monitoring temperature of the first wireless power transmitter.

26. The medium of claim 25, the method further comprising receiving a measurement of the first current from the first wireless power transmitter.

27. The medium of claim 25, wherein the frequency difference reduces the magnitude of the combined magnetic field from a first level to a second level, the second level lower than the first level and satisfying a safety threshold magnetic field emissions level.

28. The medium of claim 25, the method further comprising:

identifying a first phase of the first current provided to the first wireless power transmitter;

determining a second phase to provide the second current to the second wireless power transmitter such that a phase difference between the first phase and the second phase reduces the combined magnetic field;

determining the time to provide the second current to the second wireless power transmitter; and

providing the second current with the second phase to the second wireless power transmitter at the determined time.

29. The medium of claim 28, wherein identifying the first phase is based on the measurement of the first current received from the first wireless power transmitter.

30. The medium of claim 28, the method further comprising measuring the first phase and/or a temperature of the first wireless power transmitter via a sensor circuit.